The silver nanoparticles (AgNPs) are synthesized by various methods and seem to be very hazardous to the ecosystem and expensive. Hence, the present study aimed to synthesize homogeneous silver nanoparticles (AgNPs) using Coccinia grandis (L.) Voigt leaf extract with procedures non-toxic, and eco-friendly. The formation of biologically synthesized AgNPs was characterized by UV-Visible spectrophotometer (UV-Vis) and the transmission electron microscope (TEM) techniques. The formation of the AgNPs was observed visually with the color change of the solution from yellow to reddish-brown. The UV-Vis spectroscopy showed the maximum absorbance wavelength of Ag0 at 469 nm. The TEM demonstrated AgNPs with an average particle diameter of 19.02 nm and clearly indicated the shape of AgNPs in solution is spherical and well dispersed. The density functional theory (DFT) studies reveal that the quercetin in Coccinia grandis (L.) Voigt leaf extract behaves as a reducing agent for the reduction of Ag+ ions into Ag0. This research opens up new options for the synthesis of size-controlled, large-scale, biocompatible using an inexpensive and non-toxic extract as a reducing and stabilizing agent.